NuGetCommand@2 restore always picks some old .NET SDK version on custom agent

##[error]The nuget command failed with exit code(1) and error(c:\w\_tool\dotnet\sdk\6.0.428\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(144,5): error NETSDK1045: The current .NET SDK does not support targeting .NET 8.0.  Either target .NET 6.0 or lower, or use a version of the .NET SDK that supports .NET 8.0. [c:\w\21\s\Webjobs\<proj_name>\<proj_name>.csproj]

- task: UseDotNet@2
    displayName: 'Install .NET SDK 8.0'
    inputs:
      packageType: 'sdk'
      version: '$(sdk_version)'
      installationPath: '$(Agent.ToolsDirectory)/dotnet'

- task: NuGetCommand@2
    displayName: NuGet restore
    inputs:
      command: 'restore'
      restoreSolution: 'MySoln.sln'
      feedsToUse: 'config'
      nugetConfigPath: 'NuGet.config'